The invention concerns a method and a device for the accumulation of an overlength of yarns between a bobbin creel and the beam on a beaming machine. Such methods and devices serve the purpose, for example on a sectional warping plant, of enabling the uncovering of broken yarns that have continued to be wound prior to the beam coming to rest, without the formation of slack in individual yarns between the bobbin creel and the beaming machine. The unbroken yarns are accumulated with a definite yarn tension and in an ordered field, to be rolled out after repair of the broken yarn prior to the plant resuming its normal operating speed.
German patent document DA 41 31 489 discloses a comparable and related device wherein the yarn warp is held with the aid of two warp clamping rollers prior to the reversal of the beam and the actual accumulation procedure. Reverse rotation of the beam and displacement of the accumulator rollers is synchronous, the drive control for maintenance of yarn tension ensuing via a jockey roller. Other state of the art methods and devices operate according to the same principle, with the yarns being clamped continuously on the bobbin creel side.
A disadvantage of state of the art methods is that exact speed synchronisation between the accumulator device and the machine can only be achieved with difficulty and requires a relatively complicated control mechanism. Because the yarns are clamped on the creel side, even slight differences in speed can lead to over-stretching of the yarns to their break point, or to a drop below a minimum tension as soon as the jockey roller has reached its end position. Additionally, it is necessary to immediately open the yarn web clamp as soon as the accumulated yarn length has been rewound onto the beam, otherwise the clamping beam used for clamping the yarns on the creel side will lead to pinching of the yarns and subsequent fibre damage.